# std::ranges::basic_istream_view::iterator

From cppreference.com
< cpp‎ | ranges‎ | basic istream view

struct /*iterator*/; |  | (exposition only*)

ranges::basic_istream_view<Val, CharT, Traits>::`iterator` is the type of the iterators returned by `begin()` of ranges::basic_istream_view<Val, CharT, Traits>.

`iterator` is an `input_iterator`, but does not satisfy LegacyInputIterator, and thus does not work with pre-C++20 algorithms.

### Nested types

Type | Definition
`iterator_concept` | std::input_iterator_tag
`difference_type` | std::ptrdiff_t
`value_type` | `Val`

### Data members

Member | Definition
ranges::basic_istream_view<Val, CharT, Traits> `parent_` | a pointer to the parent view (exposition-only member object*)

### Member functions

## std::ranges::basic_istream_view::iterator::iterator

/*iterator*/( const /*iterator*/& ) = delete; | (1) | (since C++20)
/*iterator*/( /*iterator*/&& ) = default; | (2) | (since C++20)
constexpr explicit /*iterator*/( basic_istream_view& parent ); | (3) | (since C++20)

1) The copy constructor is deleted. The iterator is not copyable.
2) The move constructor is defaulted.
3) Initializes `parent_` with std::addressof(parent).

## std::ranges::basic_istream_view::iterator::operator=

/*iterator*/& operator=( const /*iterator*/& ) = delete; | (1) | (since C++20)
/*iterator*/& operator=( /*iterator*/&& ) = default; | (2) | (since C++20)

1) The copy assignment operator is deleted. The iterator is not copyable.
2) The move assignment operator is defaulted.

## std::ranges::basic_istream_view::iterator::operator++

/*iterator*/& operator++(); | (1) | (since C++20)
void operator++(int); | (2) | (since C++20)

1) Equivalent to *`parent_`﻿->`stream_``` >>`` `parent_`﻿->`value_`.
2) Equivalent to ++*this.

## std::ranges::basic_istream_view::iterator::operator*

Val& operator*() const; |  | (since C++20)

Returns `parent_`﻿->`value_`.

### Non-member functions

## operator==(std::ranges::basic_istream_view::iterator, std::default_sentinel)

friend bool operator==( const /*iterator*/& x, std::default_sentinel_t ); |  | (since C++20)

Returns !*`parent_`﻿->`stream_`.

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when `std::ranges::basic_istream_view::iterator` is an associated class of the arguments.

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
P2325R3 | C++20 | default constructor was provided as C++20 iterators must be `default_initializable` | removed along with the requirement

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/basic_istream_view/iterator&oldid=176951"